The title compound, C13H12N4O2, crystallized with two independent molecules (A and B) in the asymmetric unit. Molecule B is planar to within 0.044 (3) Å for all non-H atoms, while molecule A is slightly twisted, with a dihedral angle of 6.29 (4)° between the mean planes of the pyrazine-2-carbohydrazide and 1-(2-hydroxyphenyl)ethanone moieties (r.m.s. deviations = 0.0348 and 0.0428 Å, respectively). S(5) and S(6) ring motifs are formed in both molecules due to the presence of intramolecular O-HN and N-HN hydrogen bonds. In the crystal, molecules A and B are linked by a C-HO hydrogen bond. They stack along the a-axis direction, forming columns with - interactions involving inversion-related pyrazine and benzene rings [centroid-centroid distances = 3.5489 (13)-3.8513 (16) Å].

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: SU2634 ).

Acknowledgements

The authors acknowledge the provision of funds for the purchase of the diffractometer and encouragement by Dr Muhammad Akram Chaudhary, Vice Chancellor, University of Sargodha, Pakistan, and also thank the Higher Education Commission (HEC) of Pakistan for financial support. MA is grateful to the Pakistan Council of Scientific and Industrial Research (PCSIR) Laboratories of Pakistan for financial support through out his study leave.

This is an open-access article distributed under the terms of the Creative Commons Attribution Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.